GB2312434A - Ink and toner compositions based on water-solubilising-group-free 4-(2-(bromo/chloro)-3,6-dichloro-4-fluorosulphonylphenyl)azoaniline monoazo dye derivatives - Google Patents

Abstract

An ink composition comprises: (i) a monoazo dye which is free from water-solubilising groups and has the Formula (1): wherein: ```Q is -Br or -Cl; R 1 and R 2 each independently is -H, optionally substituted C 1-6 -alkyl or optionally substituted aryl; and R 3 , R 4 , R 5 and R 6 each independently is -H, -F, -Cl, -Br, -I, -SO 2 F or C 1-6 -alkyl, C 1-6 -alkoxy, C 1-4 -alkanoylamino, -NHSO 2 alkyl or -O-phenyl each of which is optionally substituted; and (ii) a medium comprising a low melting point solid, an organic solvent, or a mixture of water and one or more water-soluble organic solvent(s). A toner resin composition comprises a toner resin and a dye of the Formula (1). Also claimed is a process for ink jet printing of a substrate with the inks and a process for ink jet printing of a textile material with the inks.

Description

COMPOSITIONS. PROCESSES AND USES The present invention relates to compounds particularly to compositions and solutions thereof, suitable for use in printing and imaging technologies, especially those suitable for coloration of substrates such as paper1 plastics1 textiles, metal and glass by printing processes such as ink jet printing and those suitable for use in electrophotography such toners.

Ink jet printing is a non-impact printing technique which involves ejecting, thermally or by action of an oscillating piezo crystal, droplets of ink continuously or on demand from a fine nozzle directly onto a substrate such as paper, plastics, textile, metal or glass. The ink may be aqueous, solvent or hot melt based and must provide sharp, non-feathered images which have good waterfastness, light fastness and optical density, have fast fixation to the substrate and cause no clogging of the nozzle.

Electrophotographic copiers or printers generally comprise an organic photoconductor (OPC) and a developer or toner. The OPC generally comprises an electrically conducting support, a charge generating layer and a charge transport layer.

The electrically conducting support is a metal drum, typically an aluminium dam, or a metallised polymer film, typically aluminised polyester. The charge generating layer comprises a charge generating material (CGM) and a binder resin, typically a polycarbonate. The charge transport later comprises a charge transport material (CTM) and a binder resin, typically a polycarbonate. The developer or toner comprises a toner resin, a colorant and optionally a charge control agent (CCA). The toner resin is typically a styrene or substituted styrene polymer or styrene-butadiene copolymer. The colorant is typically a dye or pigment or mixture thereof.

International patent application published as WO 95/20014 describes azo compounds which contain at least one fluorosulphonyl group and are free from watersolubilising groups.

It has now been found that certain dyes falling within the general class described in WO 95/20014 but not specifically disclosed therein exhibit advantageous properties in ink compositions for use in ink jet printing.

According to the present invention there is provided an ink composition comprising: (i) a monoazo dye which is free from water-solubilising groups and has the Formula (1):

Formula (1) wherein: Q is -Br or -Cl; R1 and R2 each independently is -H, optionally substituted C1-6-alkyl or optionally substituted aryl; and R3, R4, R5 and R6 each independently is -H, -F, -Cl, -Br, -I, -SO2F or C1-alkyl, Cr 6- alkoxy, C1-4-alkanoylamino, -NHSO2alkyl or -Ophenyl each of which is optionally substituted; and (ii) a medium comprising a low melting point solid, an organic solvent, or a mixture of water and one or more water-soluble organic solvent(s).

Water-solubilising groups which must be absent from the dyes of Formula (1) particularly include -SO3H, -CO2H, -PO3H and quatemary ammonium groups and salts thereof.

The optional substituents for groups represented by R1 to R6 particularly include -CN, -OH, -OCOC-alkyl, -COOC1 6-alkyl, phenyl, phenoxy, -OCOphenyl, -COphenylSO2F, phenylSO2F, -OphenylSO2F, -CO2phenylSO2F, -COOC1alkylOCOC1 - 6-aikyl and -COOC16-alkylCOOC1~6-alkyl.

A preferred subgroup of the dyes of Formula (1) comprises compounds of the Formula (2):

Formula (2) wherein: Q is as hereinbefore defined; and R1 and R2 each independently is optionally substituted C1-6-alkyl.

Within the sub-group of Formula (2), particular mention may be made of dyes in which each of R1 and R2 is optionally substituted ethyl, for example dyes in which R' is -C2H5 and R2 -C2H4X wherein X is selected from -H, -CN, -COOC2H5, -OCOCH3 and -oC6H5 The dyes of Formula (1) may be prepared by diazotising 6-bromo-2,5-dichloro4 fluorosulphonylaniline or 2, 3,6-trichlornA-fluornsulphonylaniline and coupling the resulting diazo compound with an aromatic amine of the Formula (3):

Formula (3) wherein R1 to R6 are as hereinbefore defined.

The diazotisation and coupling reactions may be performed using conditions conventionally employed for the type of reactant involved. Typically, the ibromo-2,5- dichlornfluornsulphonylaniline or 2,3,6-trichloro4-fluorosulphonylaniline may be diazotised in an acidic medium, for example acetic, propionic or hydrochloric acid using a nitrosating agent, for example nitrosylsulphuric acid, sodium nitrite or methyl nitrite at a temperature from -10 C to 1000. Coupling with the aromatic amine of Formula (3) may be achieved by adding the diazotised 6-bromo-2,5-dichloro4-fluorosulphonylaniline or diazotised 2,3,6-trichloro-4-fluorosulphonylaniline to the amine of Formula (3) in an alkanol such as methanol at a temperature from OOC to 1000. After coupling, the compound of Formula (1) may be recovered from the reaction mixture by any convenient means such as by filtration.

The 6-bromo-2,5-dichloro-4-fluorosulphonylaniline and 2,3,6-trichloro-4fluorosulphonylaniline, respectiveiy, may be obtained by bromination or chlorination of 2,5-dichloro4fluorosulphonylaniline.

The ink compositions of the present invention preferably contain from 0.5% to 20%, more preferably from 0.5% to 15%, and especially from 1% to 3%, by weight of the dye of Formula (1) based on the total weight of the ink.

When the liquid medium is a mixture of water and one or more water-soluble organic solvents, the weight ratio of water to organic solvent(s) is preferably from 99:1 to 1:99, more preferably from 99:1 to 50:50 and especially from 95:5 to 80:20. The water-soluble organic solvents is preferably selected from Ca4-alkanols, for example methanol, ethanol, npropanol, isopropanol, n-butanol, sec-butanol, tert-butanol and isobutanol; cyclic alkanols, for example cyclohexanol and cyclopentanol, amides for example dimethylformamide or dimethylacetamide; ketones or ketone-alcohols, for example acetone or diacetone alcohol; ethers, for example tetrahydrofuran or dioxane; oligo- or poly-alkyleneglycols, for example diethylene glycol, triethylene glycol, polyethylene glycol and polypropylene glycol; alkyleneglycols or thioglycols containing a C2-C6-alkylene group, for example ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol and thiodiglycol; polyols, for example glycerol or 1,2,6-hexanetriol; C14-alkyl-ethers of polyhydric alcohols, for example 2-methoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)-ethanol, 2 [2-(2-methoxyethoxy)ethoxy]ethanol and 2-[2-(2-ethoxyethoxy)-ethoxy]-ethanol; heterocyclic ketones, for example 2-pyrrolidone and N-methyl-2-pyrrolidone; or mixtures containing two or more of the aforementioned water-soluble organic solvents, for example thiodiglycol and a second glycol or diethylene glycol and 2-pyrrolidone.

Preferred water-soluble organic solvents are 2-pyrrolidone; N-methyl-pyrrolidone; alkylene- and oligo-alkylene-glycols, for example ethyleneglycol, diethyleneglycol, triethyleneglycol; and lower alkyl ethers of polyhydric alcohols, for example 2-methoxy2-ethoxy-2-ethoxyethanol; and polyethyleneglycols with a molecular weight of up to 500. A preferred specific solvent mixture is a binary or temary mixture of water and diethylene glycol and/or, 2-pyrrolidone or N-methylpyrrolidone in weight ratios 75-95:25-5 and 60-80:020:0-20 respectively.

When the medium comprises water and one or more water-soluble organic solvent(s) it preferably contains a dispersing agent and a defoamer.

Suitable dispersing agents include for example, lignosulphonates, a naphthalene sulphonic acidiformaldehyde condensate and a phenollcresollsulphanilic acid/formaldehyde condensate. The dispersing agent is preferably present at from 0.25 to 20% based upon the total weight of the ink composition.

Suitable defoamers include for example, nonanol and silicon based mineral oils.

The defoamer is preferably present at from 0.05 to 2% based upon the total weight of the ink composition.

In view of the foregoing preferences a preferred ink composition comprises: (a) 0.5 to 20 parts of the dye; (b) 2 to 60 parts of water-soluble organic solvent(s); (c) 1 to 95 parts water; (d) 0.5 to 20 parts dispersing agent; and (e) 0.05 to 2 parts defoamer; wherein the parts (a)+(b)+(c)+(d)+(e) = 100.

In addition to the parts (a) to (e) the ink may contain other components conventionally used in ink jet ink formulations, for example a biocide, surfactants, viscosity modifiers, corrosion inhibitors and kogation reducing additives.

Examples of further suitable ink media are given in US 4,963,189, US 4,703,113, US 4,626,284 and EP 4,251,50A.

When the liquid medium is an organic solvent, the solvent is preferably selected from ketones, alkanols, aliphatic hydrocarbons, esters, ethers1 amides or mixtures thereof. Where an aliphatic hydrocarbon is used as the solvent a polar solvent, for example an alcohol, ester, ether or amide is preferably added. Preferred solvents include ketones, especially methyl ethyl ketone and alkanols especially ethanol and n-propanol.

Organic solvent based ink compositions are used where fast drying times are required and particularly when printing onto hydrophobic substrates, for example plastics, metal or glass.

When the medium is an organic solvent, it is preferred that the dye of Formula (1) is dissolved completely in the medium to form a solution.

When the medium for the ink composition is a low melting point solid the melting point of the solid is preferably in the range from 60"C to 125"C. Suitable low melting point solids include long chain fatty acids or alcohols, preferably those with CS24 chains, or sulphonamides. The dye of Formula (1) may be dissolved in the low melting point solid or may be finely dispersed in it.

It is preferred that the pH of the ink composition is less than 7, more preferably in the range of from 2 to 6.5 and especially from 4 to 6 to prevent hydrolysis of the -SO2F group present in the dye of Formula (1).

According to a second aspect of the present invention there is provided a process for printing a substrate with an ink composition using an ink jet printer, characterised in that the ink composition is as defined for the first aspect of the present invention.

A suitable process for the application of an ink composition as hereinbefore described comprises fonning the ink into small droplets by ejection from a reservoir through a small orifice so that the droplets of ink are directed at a substrate. This process is commonly referred to as ink jet printing, and preferred ink jet printing processes for the present inks are piezoelectric ink jet printing and thermal ink jet printing. In thermal ink jet printing, programmed pulses of heat are applied to the ink in the reservoir by means of a resistor adjacent to the orifice, during relative movement between the substrate and the reservoir.

Preferred substrates include overhead projector slides or papers, including plain and treated papers, which may have an acid, alkaline or neutral character or textile materials, preferably synthetic textile materials and fibre blends thereof.

The synthetic textile material is preferably selected from secondary cellulose acetate, cellulose triacetate, polyamide, polyacrylonitrile and aromatic polyester. The synthetic textile material is more preferably polyamide, for example polyhexamethylene adipamide or aromatic polyester, especially polyethylene terephthalate. Fibre blends preferably comprise mixtures of different synthetic textile materials or mixtures of synthetic and natural textile materials. Preferred fibre blends include those of polyester cellulose for example polyester-cotton. The textile materials or blends thereof may be in the form of filaments, loose fibres, yam or woven or knitted fabrics.

The preferred ink used in the process is as hereinbefore described.

The ink compositions according to the first aspect of the present invention colour substrates with yellow-brown shades exhibiting good fastness to washing, light and heat.

According to a third aspect of the present invention there is provided a paper or an overhead projector slide or a textile material printed with an ink composition according to the first aspect of the present invention, or by means of the process according to the second aspect of the present invention.

According to a fourth aspect of the present invention there is provided a process for the coloration of a textile material with an ink composition according to the first aspect of the present invention which comprises the steps :i) applying the ink composition to the textile material by ink jet printing; and ii) heating the textile material at a temperature from 50"C to 250"C to fix the dye on the material.

The process for the coloration of a textile material by ink jet printing preferably comprises a pre-treatment of the textile material with an aqueous pretreatment composition comprising a water-soluble acid and a thickening agent followed by removing water from the pre-treated textile material to give a dry pre-treated textile material which is subjected to ink jet printing in step i) above.

The pretreatment composition preferably comprises a solution of the acid in water containing the thickening agent.

The acid is present in the pretreatment composition to provide a pH of less than 7, preferably a pH in the range of 2 to 6, on the surface of the fabric. The acidic medium on the surface of the fabric ensures that the dye chromophore is not decomposed during the dyeing process, as can be the case if the pH exceeds 7. It is preferred that the acid is a non volatile acid, more preferably a non volatile organic acid, for example citric acid or tartaric acid. The acid is present in the pretreatment composition at a concentration sufficient to give a pH in the range of 2 to 6. When the acid is citric or tartaric acid it is convenient to use from 1% to 5% acid based upon the total weight of the pretreatment composition.

The thickening agent may be any thickening agent suitable for use in the preparation of print pastes for the conventional printing of cellulose reactive dyes.

Suitable thickening agents include alginates, especially sodium alginate, xantham gums, monogalactam thickeners and cellulosic thickeners. The amount of the thickening agent can vary within wide limits depending on the relationship between concentration and viscosity. However, sufficient agent is preferred to give a viscosity from 10 to 1000 mPa.s, preferably from 10 to 100 mPa.s, (measured on a Brookfield RVF Viscometer).

For an alginate thickener this range can be provided by using from 10% to 20% by weight based on the total weight of the pretreatment composition.

The remainder of the pretreatment composition is preferably water, but other ingredients may be added to aid fixation of the dye to the textile material or to enhance the clarity of print by inhibiting the diffusion (migration) of dye from coloured areas to noncoloured areas before fixation.

Examples of fixation enhancing agents are cationic polymers, such as a 50% aqueous solution of a dicyanamide/phenol formaldehydelammonium chloride condensate e.g. MATEXILTM FC-PN (available from ICI), which have a strong affinity for the textile material and the dye and thus increase the fixation of the dye on the textile material.

Examples of anti-migration agents are low molecular weight acrylic resins, e.g.

polyacrylates, such as poly(acrylic acid) and poly(vinyl acrylate).

However, when further agents are added to the pretreatment composition, care must be taken to balance their effects and to avoid interactions with the other ingredients of the composition.

In the pre-treatment stage of the present process the. pretreatment composition is preferably evenly applied to the textile material. Where a deeply penetrated print or a deep shade is required the pretreatment composition is preferably applied by a padding or similar process so that it is evenly distributed throughout the material. However, where only a superficial print is required the pretreatment composition can be applied to the surface of the textile material by a printing procedure, such as screen or roller printing, ink jet printing or bar application.

In the pre-treatment stage of the present process, water may be removed from the pre-treated textile material by any suitable drying procedure such as by exposure to hot air or direct heating, e.g. by infra-red radiation, or micro-wave radiation, preferably so that the temperature of the material does not exceed 10000.

The application of the ink composition to the textile material, stage (i) of the present process, may be effected by any ink jet printing technique, whether drop on demand (DOD) or continuous flow. The ink composition, preferably also contains a humectant to inhibit evaporation of water and a preservative to inhibit the growth of fungi, bacteria and/or algae in the solution. Examples of suitable humectants are, propan-1,2diol, butan-1,2-diol, butan-2,3-diol and butan-1,3-diol, urea, caprolactam and polyethylene glycols. Where the ink jet printing technique involves the charging and electricallycontrolled deflection of drops the composition preferably also contains a conducting material such as an ionised salt to enhance and stabilise the charge applied to the drops.

Suitable salts for this purpose are alkali metal salts of mineral acids.

After application of the ink composition, it is generally desirable to remove water from the printed textile material at relatively low temperatures ( < 100 C) prior to the heat applied to fix the dye on the textile material as this has been found to minimise the diffusion of the dye from printed to non-printed regions. As with the pretreated textile material removal of water is preferably by heat, such as by exposure to hot air or to infrared or micro-wave radiation.

In stage (ii) of the present process, the printed textile material is submitted to a short heat treatment, preferably after removal of water by low-temperature drying, at a temperature from 1 000 to 200 C by exposure to dry or steam heat for a period of up to 20 minutes in order to fix the dye on the textile material. If a steam (wet) heat treatment is used, the printed material is preferably maintained at 100-105 C for from 5 to 15 minutes whereas if a dry heat treatment is employed the printed material is preferably maintained at 140-160 C for from 2 to 8 minutes.

After allowing the textile material to cool, unfixed dye and other ingredients of the pretreatment and dye compositions may be removed from the textile material by a washing sequence, involving a series of hot and cold washes in water and aqueous detergent solutions before the textile material is dried.

Preferred textile materials for use in the process according to the fourth aspect of the present invention are as herein before defined for the second aspect of the present invention.

According to a fifth aspect of the present invention there is provided a textile material, especially a synthetic textile material or a fibre blend, coloured by means of the process according to the fourth aspect of the present invention.

According to a sixth aspect of the present invention there is provided a toner resin composition comprising a toner resin and a dye, characterised in that the dye is of Formula (1).

The toner resin is a thermoplastic resin suitable for use in the preparation of. toner compositions. A preferred toner resin is a styrene or substituted styrene polymer or copolymer such as polystyrene or styrene-butadiene copolymer, especially a styreneacrylic copolymer such as a styrene-butyl methacrylate copolymer. Other suitable toner resins include polyesters, polyvinylacetate, polyalkenes, polyvinylchloride, polyurethanes, polyamides, silicones, epoxyresins and phenolic resins. Examples of toner resins are given in Electrophotography by R.M.Scharfert (Focal Press), US 5143809, UK 2090008, US 4206064 and US 4407928.

The toner resin composition preferably contains from 0.1% to 20% of the dye of Formula (1) more preferably from 3% to 10% based on the total weight of the toner resin composition.

The toner resin composition may be prepared by any method known to the art which typically involves mixing the toner resin with the dye of Formula (1) and optionally a charge control agent (CCA) by kneading in a ball mill above the melting point of the resin.

Generally, this involves mixing the molten toner resin composition for several hours at temperatures from 120 to 200"C, in order to uniformly distribute the optional OCA and dye throughout the toner resin. The toner resin is then cooled, crushed and micronised until the mean diameter of the particles is preferably below 20pm and, for high resolution electroreprography, more preferably from 1 to 1 011m. The powdered toner resin composition so obtained may be used directly or may be diluted with an inert solid diluent such as fine silica by mixing for example in a suitable blending machine.

CCA's are more fully described in W094123344.

Example 1 To a solution of 2,5-dichloro-4-fluorosulphonylaniline (4.9 parts) in acetic acid (30 parts) stirring at ambient temperature, was added a solution of bromine (3.52 parts) in acetic acid (10 parts). The mixture was stirred for 2 hours at 700C, cooled to ambient temperature and water (75 parts) was added. After stirring for 1 hour, the product was isolated by filtration and dried to yield; 6-bromo-2,5-dichloro4-fluorosulphonylaniline (6.0 parts).

To a mixture of 6-bromo-2,5-dichloro-4-fluorosulphonylaniline (2.6 parts) and acetic/propionic acid mixture (15 parts, 86114 vovol), stining at 0-5 C, was added dropwise nitrosylsulphuric acid solution (5 parts). The mixture was stirred at this temperature for a further 30 minutes.

The diazo solution was added slowly to a mixture of N,N-diethylaniline (1.2 parts), methanol (20 parts), water (10 parts) and sulphamic acid (0.5 part), stirring at 0-5 C.

After stirring for 3 hours at this temperature, the product was isolated by filtration, washed with water and dried to yie Id yield 4-(6-bromo-2,5-dichloro4-fluorosulphonylphenylazo)-NN- diethylaniline (1.3 parts).

When applied to polyester materials from an aqueous dispersion, the dye gives yellow brown shades with excellent light fastness and excellent fastness to wet treatments. Bmax=452nm.

Example 2 In place of N,N-diethylaniline (1.2 parts) in Example 1, there were used N-ethyl-N-(2-cyanoethyl)aniline (1.4 parts) to yield 4-(6-bromo-2,5-dichloro-4- fluorosulphonyl phenylazo)-N-ethyl-N(2-cyanoethyl)aniline (1.6 parts). When applied to polyester materials from an aqueous dispersion, the dye gives yellow brown shades with excellent light fastness and excellent fastness to wet treatments. Bmax = 418nm Example 3 In place of N,N-diethylaniline (1.2 parts) in Example 1, there were used N-ethyl-N-(2-ethoxycarbonylethyl)aniline (1.5 parts) to yield 4-(6-bromo-2,5-dichloro-4- fluorosulphonylphenylazo)-N-ethyl-N-(2-ethoxycarbonylethyl)aniline (1.4 parts).

When applied to polyester materials from an aqueous dispersion, the dye gives yellow brown shades with excellent light fastness and excellent fastness to wet treatments. Smax = 436nm.

Example 4 In place of N,N-diethylaniline (1.2 parts) in Example 1, there were used N-ethyl-N-(2-acetoxyethyl)aniline (1.4 parts) to yield 4-(6-bromo-2,5-dichloro4- fluorosulphonylphenylazo)-N-ethyl-N-(2-acetoxyethyl)aniline (1.3 parts). When applied to polyester materials from an aqueous dispersion, the dye gives yellow brown shades with excellent light fastness and excellent fastness to wet treatments. Xmax = 434nm.

Example 5 In place of N,N-diethylaniline (1.2 parts) in Example 1, there were used N-ethyl-N-(2-phenoxyethyl)aniline (1.7 parts) to yield 4(6-brnmo-2,5-dichlornA- fluorosulphonyl phenylazo)-Nthyl-N-(2-phenoxyethyl)aniline (1.8 parts). When applied to polyester materials from an aqueous dispersion, the dye gives yellow brown shades with excellent light fastness and excellent fastness to wet treatments. Smax = 446nm.

Example 6 In place of the N,N-diethylaniline in Example 1 them may be used N,N-diethyl-3toludine to yield 4-(6-bromo-2, 5-dichloro-4-fl uorosulphonyl phenylazo)-3-methyl-N ,N- diethylaniline.

Example 7 The following ink compositions containing the dyes described in the previous examples may be prepared according to the formulations shown in Table 1 wherein the figures denote parts by weight based upon the total weight of the ink composition.

In Table 1 Formulations A and B refer to the following ink media wherein the parts are by weight based upon the total weight of the ink composition: Formulation A Glycerol 10.0 parts; 2-pyrrolidone 5.0 parts; Nonanol (defoaming agent) 0.5 parts; Lignosulphonate (dispersing agent) 5.0 parts; and ProxelTM GXL (a biocide available from Zeneca Limited) 0.1 parts.

Formulation B Ethylene glycol 10.0 parts; N-methylpyrrolidone 5.0 parts; Sodium Dispersol (a dispersing agent available from Zeneca Limited) 5.0 parts; Proxel GXL 0.1 parts; and Nonanol 0.5 parts.

Each ink composition shown in Table 1 has 100 parts, the balance being water (i.e. 100 - dye parts - formulation parts).

The ink compositions shown in Table 1 may be applied to a substrate such as paper using an ink jet printer.

TABLE 1

Dyes from Example(s) No. Parts of Dye Formulation Balance of water (parts) 1 5 A 1 10 A 69.4 2 2 B 77.4 3 5 B 74.4 4 8 B 71.4 2 5 A 74.4 4 6 A 73.4 2 3 B 76.4 3 2.5 A 76.9 6 8.9 B 70.5 5 10 A 69.4 4 1.5 A 77.9 1 3.6 B 75.8 3 7 A 72.4

Claims (11)

1. CLAIMS 1. An ink composition comprising: (i) a monoazo dye which is free from water-solubilising groups and has the Formula (1):

   Formula (1) wherein: Q is -Br or -CI; R1 and R2 each independently is -H, optionally substituted cox 6-alkyl or optionally substituted aryl; and R3, R4, R5 and R6 each independently is -H, -F, -Cl, -Br, -I, -SO2F or C1-6-alkyl, C1-6- alkoxy, C14-alkanoylamino, -NHSO2alkyl or -Ophenyl each of which is optionally substituted; and (ii) a medium comprising a low melting point solid, an organic solvent, or a mixture of water and one or more water-soluble organic solvent(s).
2. 2. An ink composition comprising a medium and a dye of the Formula (2):

   Formula (2) wherein: R1 and R2 each independently is optionally substituted C,-alkyl; and Q and the medium are as defined in Claim 1.
3. 3. An ink composition according to either of Claims 1 or 2 wherein the medium comprises water and one or more water-soluble organic solvent(s).
4. 4. An ink composition according to any one of the preceding claims comprising: (a) 0.5 to 20 parts of the dye; (b) 2 to 60 parts of water-soluble organic solvent(s); (c) 1 to 95 parts water; (d) 0.5 to 20 parts dispersing agent; and (e) 0.05 to 2 parts defoamer; wherein the parts (a)+(b)+(c)+(d)+(e) = 100.
5. 5. An ink composition according to any one of the preceding claims wherein the pH of the ink composition is less than 7.
6. 6. A process for printing a substrate with an ink composition using an ink jet printer, characterised in that the ink composition is as defined in any one of Claims 1 to 5.
7. 7. A paper, an overhead projector slide or a textile material printed with an ink composition according to any one of Claims 1 to 5 or by means of the process according to claim 6.
8. 8. A process for the coloration of a textile material with an ink composition as defined in any one of Claims 1 to 5 which comprises the steps: i) applying the ink composition to the textile material by ink jet printing; and ii) heating the textile material at a temperature from 50"C to 250"C to fix the dye on the material.
9. 9. A textile material coloured by means of the process according to Claim 8.
10. 10. A toner resin composition comprising a toner resin and a dye, characterised in that the dye is as defined in Claim 1.
11. 11. An ink composition substantially as hereinbefore defined in any one of the examples.